Thanks for your feedback. Unfortunately, this does not quite meet customer requirements. As I understand it, there is no way to highlight individual groups of lines in color. Are there any other matrix visuals from the store that can do more in this case?
As mentioned by @amitchandak ,If you just want to change then color of head, you can change the font color\background color of row headers in "Format Pane".However, it will applied to all subtotal headers.
You can consider using conditional formatting to formate row value as below: