If you have one leading to a farm, make it green, but if the hallway is leading to your energy storage, make it green and yellow? No, what if it lead to three...okay, what if it were farm, all green, then when it was going to energy, all yellow, and when it finished at mob spawner, make the rest of it red? I am not sure. One color would be a lot easier to make, simply because you don't have to pre-designate all your rooms before you start your build.
I think it's a bit harder for me to help you now
But, a central room leading to different rooms (storage, certain mod rooms) with only one "subject" in the entire hallway would benefit from using multiple colors. Big room would be black, then hallways branching off would be the other colors.