This is technically possible.
This calendar is created with Zooper. There is an option in Zooper for setting the color code to the color assigned in the Google Calendar.
The code is #C0COLOR#, this variable will render or output an actual RGB color code for what ever color is assigned to that event in your Google Calendar.
So you have this variable, and I am sure you are wondering WTH you would do with it.
We assuming that the text in that calendar is RichText and not regular text you can assign a BBCODE around the Event variable that changes its color.
Lets say its the event title for the first event, #C0TITLE#. If you want this to be the correct color that is assigned to it you would change it to the following. [c#C0COLOR#]#C0TITLE#[/c]
If it were for the second event it would be as follows.
[c#C1COLOR#]#C1TITLE#[/c]
All in all you CAN do this. It just matters if you want to take the time to change it yourself, getting your hands dirty with a little light coding.
Hope this helps.