You can define monitors for local stresses or strains the same way as for displacements or forces/reactions, and then use them in a graph.
If you like to directly compare the curve to a measurement, you need to define your monitors the same way in the model as in the reality, e.g., for a strain gauge 20mm long, you should define 2 displacement monitors 20mm apart and subtract their values in a spreadsheet, see also ATENA Troubleshooting, 2.2.20 How can I see the numerical values of monitors and export them into a spreadsheet? The latest version of the document is available from our web (Products - ATENA - Documentation).