There may come a time when you want or need to change the default colour for a data source.
On the left hand side of the Options tab is a list of source and their currently associated colours.
Click on the coloured box or on the Source Name to open the color picker.
Choose your desired colour and click OK when done. Mac's may need to simply close the colour picker box to accept the colour choice.
The default colours for each source are:
23andMe: Dark Green
FTDNA: Reddish Brown
Gedmatch: Purple
CoA: Deep Green
Archived: Yellowish Brown
MyHeritage: Bright Green
Your current colours may vary from the default for a variety of reasons, including having previously changed the color.