It becomes interactable once you finish the escape room - rather than exiting it take a left.
After a shamefully long time (during which I tried to brute force the code, twice), I finally got to the color part, and let me tell ya. This part. I cannot for the life of me get it all the rules to mesh together. I think I've got it worked out, for the most part, but that one of there are only two colors that appear once or whatever always trips me up. *Edit* yeah, after scrolling through the other replies, which I probably should have done from the get-go, I found that guy who posts a pic and answers it. I would have never gotten that. I was thinking mirrored like there's a collum on the left side and a collum on the right. Anyways, awesome game.