For visualization purposes, it may be useful to have plot labels angled so they follow the curve of the plot line. This functionality has been added into the newest Grapher update. 

1. Select the plot.
2. Click on the Labels tab in the Property Manager.
3. In the Label Position section, check the box next to Label along line.
4. If desired, change the Horizontal alignment, Vertical alignment, and/or Offset along line to get the labels to the desired location. Individual labels can still be moved with the Move Labels command.

This also applies to plot titles. For more information, see here: Display plot names on line plots. 

Updated March 10, 2020