If you have Custom Colours set under the Calendar Configuration menu, you will now have the option to select a colour for each Service which will appear on the Calendar for easier viewing.
From the Dashboard, click Configure.
In the Basic Settings tab you will not have the option to pick a colour. Click the coloured box next to Colour.
Either enter the hex code (ex. #000000) for a specific colour you have in mind, or select a colour using the Colour Selection box and the Hue bar to get the desired colour then click OK.
Click Update to save changes.