1. Enable the page outline and margin outline by clicking Layout | Display | Page Outline and Layout | Display | Margins. This will make it clear where the graph lies on the page:
2. Click one of the axes in the Object Manager to select it.
3. In the Property Manager, click on the Axis tab.
4. Change the Length to an appropriate size for the page. 
5. Repeat steps 2-4 for the other axis. 
6. Click on the Graph object in the Object Manager.
7. Click and drag the graph to the desired location so that the entire graph fits within the margins on the page.

Note that if you have multiple X or Y axes, the lengths and locations may need to be adjusted for each axis if the axes lengths are not linked to one another.

Updated July 17, 2019