From the website: "Printing Graphs
Currently, graphs can only be printed directly using Internet Explorer. If you are using Firefox or Safari, you can create screenshots manually (see Print fix on gbsupport.blogspot.com) or use the PDF (Print) link located at the top of this page. This is a Firefox/Safari/Flash issue and unfortunately there are no other known work-arounds at this time."
The screen capture from your iPhone should look like
this:
