How can I set different colors for each absence type on the calendar?

Calendar configuration - employee profile

Each user can override the company settings with his/her personal settings

1. Go to User profile (bottom left corner)
2. Tick Activate custom settings
3. Under Use color to show change the default setting from Absence status to Absence type
4. Click Save

Calendar configuration - organisation

As an Admin you can change configuration for all users.

1. Open Configuration →Account settings and find Use color to show
2. Change the default setting from Absence status to Absence type
3. Click Save