How to plot voltage vs current graph on Proteus Software?
I found this thread:


  You have to use the DC sweep graph. Insert in a schematic and double click it, the default variable is X, set the range of simulation
  values and open the voltage source properties, select manual edit and
  use X in the value property of the supply. Add a current probe for the
  [load] current and add it to the graph (you can use drag and drop),
  then set the cursor over the graph and click space.


Another thing you could do is use the oscilloscope and use input A as the voltage, and input B as the current. 

Source: Engineering Projects