Once your graph is ready, you can print it.
Click File on the top of the CalGraph menu, and then Print. The print menu opens, one that looks much the same as the one you get when you print from your other programs. You can choose the Number of Copies to print, and which Printer to use (if you have more than one). You probably have a button called Preferences or Options which allows you other choices depending on the printer you selected.
When you have made your choices click on Print. CalGraph thinks carefully before it prints. You will see and hear your hard drive working hard, perhaps for 40 seconds before anything happens, and perhaps a total of 1 minute or more until the printing is finished. Be patient and don't click on anything.
The resulting graph will fill the full sheet of paper (unless you made a different selection under Preferences). It will be very like the graph window of CalGraph, though the lines will be thinner.
If you want to the graph to be different, you might want to copy the graph to another program and edit it in that program.
For safety's sake, it is a good idea to save a graph before printing it.