There are a number of ways to modify the diagram display. Many of them are available on the "Diagram Settings" tab.
Let's say you have a diagram with only a few crashes on it, and you want to annotate it or simply spread the crashes out so that they each have more space. Click on the Diagram Settings tab. "Spacing" is the distance between each of the crash graphics. The default spacing is 50. Click on the number 50 and change it to 200. While we're at it, let's also uncheck the "Display legend" checkbox. This will remove the legend from the bottom of the page.
Click on the Diagram Report tab to return to the diagram and see your changes.