I don't remember seeing any color conventions in Computer Science used to represent some abstract information or to simplify diagrams.
For instance, chemists have the CPK coloring which associates elements to colors.
Electrical technicians have the electronic color code for resistors and wire colors (black for neutral/ground red for phase).
Physicists have conventions for magnets (North pole red, South pole blue), and even quarks have colors!
In CS, one of the only cases I know of are red-black trees, but it's not so much the concepts themselves, but this particular implementation.
I'm asking because I wonder if these colors could be useful in some contexts, for instance: if CFGs were always depicted with a given color for starting node and a different one for ending node; or in programming languages, having something as "immutable data is green, mutable data is blue", or in cryptography ("hash functions are yellow, symmetric encryption is blue, asymmetric is orange"), or computer architecture ("processors are red, memory is blue, buses are green"), etc. I've never seen for instance UML color conventions, or in automata theory, or other areas which frequently use diagrams. Apart from the very universal conventions of "green = good/pass, red = bad/stop", nothing seems to stick.