You can not change the axis labels in the generated graph, you can only customise the legend at the bottom.
Is there a way that you can include the unit of measure on the axis? For instance, if I am graphing the amount of free space on an array over a three month period, is it possible to have the y-axis labeled with (TB) to specify that I am using Terabytes as my unit of measure? Thank you in advance!
Customizing Graphs in Reports