Locations can be styled by clicking the "Locations" button in the spreadsheet toolbar. It is possible to customize the location color as well as the location icon that is displayed on the map. The default icon is a simple dot or circle.
It is possible to style an entire group of locations. This is done by assigning the "Category" column type to the column that you would like to group by. After that has been completed, you will be presented with a "Group by category" toggle in the "Locations" dropdown. You can then use the arrows to toggle between the styles of each group.