Current behavior is that colors are deterministic based on group member names if you're only in one group, but if you're in multiple groups then it's set by the group's color (set in the Group Setting...
It would be aqes me if when a calendar was assigned a colour it showed on the unified view in that colour. So say you have a personal, work, and family calendar. Each has its own colour. When I look at the standard view or full month view, if each entry showed up in the colour of the calendar its in that would make at a glance viewing awesome.