That's not great. If you can use color, you can work around it, mostly, like this. (Oops. I should not have left that purple spline there!)
South Dakota
To get that, I added Detailed Earth.
Several map layers. States + Counties makes a subtle difference.
Then I changed these
Clip the detailed earth. Move it up in the list to draw first.
and this
States and Counties. Not clipped, and bolder and transparent, to your taste.
And this
Make the graph's background muted.
Along the way I played with the marker size to make it stand out a bit amongst the extra noise.
The order of the items in the Customize Graph selector box is important; the solid map needs to be drawn first so other bits can draw on top of it.
Craige