While being aware of various ways to solve this problem. Mine is to fold the cable in half, then half again, then half again until it's small enough to go into a pocket. Then store it somewhere where it will not get moved around very much, and be encouraged to tangle. The only disadvantage is that this doesn't always suit the twist of the cable, so the cable will sometimes twist around itself a few times, but never form a knot (in my experience).

You might find that owing to manufacturing process, multicoloured cables are a bit of a pain to make. We usually make very long rolls of wire with identical sleeves. Then cut down the wire to make relevant size pieces. This idea would require doing things differently.