Following your link I found https://github.com/owncloud/calendar/issues/1002 and the second comment has a solution that fixes the problem for me. I did a vimdiff on his file and without understanding much I can tell you that the changes look reasonable. I have only been testing for 5 minutes but so far it works.
Change calendar color on device
I am using davdroid 0.4. with Baikal 2.7.3 . I have multiple calenders in Baikal an can import them all. Unfortunately they all have the same color and I can not adjust this at my Baikal server. Is there any way to change this for each calendar in the app?
Thanks in advance!
Please see #136.