on the Explore screen, there’s currently not an easy way for most people to change the color or style of the markers. i’m not sure what your use case is exactly, but you could always make a feature request to provide folks a way to change the marker colors.
alternatively, you could always make your own custom map, which would give you many more options for styling, but there are also other mapping screens and tools that might provide another way to visualize the information the way you like.