Yes, you can do so pretty easily.

1) Navigate to the ''View'' Tab of the Graph
2) Hover over the buttons above the grahp. One of the buttons toward the far right will display ''Edit Categories.'' Click this button.
3) Select the Edit X-Axis Categories (Or you can just press Alt+X)
4) Click the New button
5) In the Category Name, change the text '''' to ''Automated''
6) Select the Test Types you want to group together and place them in the right pane with the ''>'' button.
7) Click the OK button.
8) Click the OK button.

The Graph now shows all the automated tests in one column and the manual tests in a second columns.