Unfortunately it is not possible to measure GSR on the MAXREFDES104 currently. It measures (SpO2, HR, and biopotential based ECG). It would require the AFE in the MAXREFDES104 to be switched out for one that measures Bioimpedance (for Bioimpedance based GSR).
Another option for the MAXREFDES104 is to look into ECG-based stress detection, but you would have to develop an algorithm for this.
Finally, if you are willing to look at a different reference platform, the VSM Study Watch already has Bioimpedance-based EDA implemented.