You can define appointment time markers to add different color bands on the left side of their badges in the Calendar. See Schedule Settings: Time markers for more information about the management and the configuration of time markers.
Define appointment time markers
To define a time marker use one of the following methods.
Right-click an appointment badge in the Calendar, go to Set a time marker and select the time marker.
From the Appointment window, go to the first Show as drop-down menu and select the time marker.
Remove appointment time markers
To remove the time marker, from the Appointment window, go to the first Show as drop-down menu and select Clear.