I have seen a few unanswered questions related to this from 2013 and am hoping the "long term" has arrived.
Specifically, I am using the Interface Charts - Average bits per second and Min/Max/Avg bits per second. Currently the Transmit is Green and the Receive is Blue. I would like to be able to change this but can not find a similar named area in any of the .CHARTS files that has an effect.