Note: This feature is only available if you have colorful clips enabled in Preferences -> Appearance -> Clip style
Changing color per clip
To change clip color, click on the 3-dot menu on the top right of the clip and select Clip color. You then are given the choice between several colors.
Changing color for an entire track
To change the color for all clips on a track, click on the 3-dot menu on the track header and select Track color. You then are given the choice between several colors.
Note: Changing track color only changes the color for clips which follow the track color. If you have changed the clip color for individual clips, they won't change color if you change track color.