The category has its own color, separate from the calendar color, but it only shows in a very small portion of the event on any display (month, week, etc). I found some info on the web about how to make the category color more prominent, but I think they are replacing the calendar color with the category color altogether. The instructions on doing this are pretty confusing as well.

I would like to just increase the size of the category color to maybe 20% of the event rather than the current ~3% that is used.