The other guide currently available is for the Deusovis pack which has a texture for all colors, but other packs are missing colors, and some people might just want another way to check the keys as the lighting doesn't allow you to take a good screenshot of the entirety without getting slight discoloration. This one also comes with the hex codes for exact comparison, but I doubt that you'd ever need that.

Obviously you shouldn't be referring to this guide until you've unlocked the area in-game, but I cannot stop you.