In Outlook and OWA when you are using the Multiple calendar view feature you can assign different colors to calendars within that view. (By default the calendar color is set to automatic which means a color is assigned at random) eg When you add a Shared Calendar to your Mailbox you create a Calendar WunderBar Navigational shortcut which are documented https://msdn.microsoft.com/en-us/library/ee202589(v=exchg.80).aspx . The color that these shortcuts will be set to is set via the PidTagWlinkCalendarColor property https://msdn.microsoft.com/en-us/library/ee200641(v=exchg.80).aspx . So if you want to set the color of one of these shortcuts with a script it does require a little bit of work. First to get the shortcut Items you need to first get the CommonViews folder and then enumerate the FAI Items collection where these shortcuts are stored. Now depending if you want to the Set the Default Folder Shortcut or a Shared Folder Shortcut (or the other calendars Shortcu...
Pushing the Envelope in Messaging and Office 365 Development