How can I adjust the margins of a graph?

Margins within the graph area
Click the Set Graph Area  

button on the Graph Tools toolbar to adjust the space between the edge of the plotting area (i.e., the borders of the graph window) and any graph components or custom graphic objects. This can be accomplished by clicking the  

button and either 1) dragging the resizing squares that appear around the edges of the graph window or 2) drawing a rectangle in the place where you want the graph to be.
Note: you can also adjust margins on the Document Size and Scaling dialog (accessible by clicking the Adjust the Graph Actual Size/Scaling  

button).
Printout margins
The printout margins (the width of the distance between the edge of the paper and the beginning of the graph area) can be adjusted in the Print Preview dialog (accessed from the File menu).