hmmm, I feel like I should be able to answer this as I make a lot of cabbage salad, but I don't use a lot of useful recipes.

I like cabbage salad with japanese-type seasoning: rice vinegar, veg oil, soy sauce and sesame seeds. You could make the two types of cabbage separately and then mix them at the last minute to keep the colors from blending.

Or make a very garlicky dressing, using a blender, food processor or stick blender to mix whole cloves in with red vinegar and olive oil. Use lots of mustard seeds in the salad.