Reading your code, I see three points:

1. Your constants are not assigned the values that you think. const int RED_COLOR = (255,0,0); sets the integer constant to the value 0, i.e. the last value of a comma-separated sequence, see here. Instead, enumerate your color constants, i.e. set red=1, blue=2, etc. Or define a struct with three integer components.
2. The variable color will never be assigned the values ORANGE_COLOR, PURPLE_COLOR nor YELLOW_COLOR, because of the way you structured the expressions in the if-then-else block. If red > green && red > blue, the program will never even check whether red > green && red > blue && blue > green, because it already entered the first block. And PURPLE_COLOR is not listed in the upper if-else-block at all. Also, as orange and yellow are both mixes of red and green, I would expect some CYAN_COLOR somewhere in there to cover the shades between green and blue.
3. What is the exact type of the color sensor? It seems strange to me that it transmits its data via the length of a pulse. If it doesn't, pulseIn() is the wrong method to use. If it really does, you may have a race condition here: I guess that writing to the pins s2/s3 triggers the sensor to start the "data pulse", in which case digitalRead(sensorOut) may already return the "pulse state" instead of the "pre-pulse state" and therefore waits for a different pulse than it should. You'd need to first read sensorOut into a variable, then set s2/s3, then read your data via pulseIn using the variable you set before.

But without having the datasheet of the sensor/knowing the protocol of the sensor, this is all very volatile guesswork. Please improve your question by adding the sensor type (and maybe a wiring diagram) alongside an explanation of what you mean by "it fails". How exactly does it fail? Which part works and which doesn't?

You can also glean more insight into the state of your sketch by writing measured values to the serial monitor using Serial.println.

Reading your code, I see three points:

1. Your constants are not assigned the values that you think. const int RED_COLOR = (255,0,0); sets the integer constant to the value 0, i.e. the last value of a comma-separated sequence, see here. Instead, enumerate your color constants, i.e. set red=1, blue=2, etc. Or define a struct with three integer components.
2. The variable color will never be assigned the values ORANGE_COLOR, PURPLE_COLOR nor YELLOW_COLOR, because of the way you structured the expressions in the if-then-else block. If red > green && red > blue, the program will never even check whether red > green && red > blue && blue > green, because it already entered the first block. And PURPLE_COLOR is not listed in the upper if-else-block at all. Also, I would expect some CYAN_COLOR somewhere in there to cover the shades between green and blue.
3. What is the exact type of the color sensor? It seems strange to me that it transmits its data via the length of a pulse. If it doesn't, pulseIn() is the wrong method to use. If it really does, you may have a race condition here: I guess that writing to the pins s2/s3 triggers the sensor to start the "data pulse", in which case digitalRead(sensorOut) may already return the "pulse state" instead of the "pre-pulse state" and therefore waits for a different pulse than it should. You'd need to first read sensorOut into a variable, then set s2/s3, then read your data via pulseIn using the variable you set before.

But without having the datasheet of the sensor/knowing the protocol of the sensor, this is all very volatile guesswork. Please improve your question by adding the sensor type (and maybe a wiring diagram) alongside an explanation of what you mean by "it fails". How exactly does it fail? Which part works and which doesn't?

You can also glean more insight into the state of your sketch by writing measured values to the serial monitor using Serial.println.