I think the overall equation is:
Fe2+ (aq) +Ag+ (aq) ------------> Fe3+ (aq) +Ag(s)
Because obviously, they both are either gaining/losing only one electron so when writing the overall equation, these two electrons cancel and also, since Fe3+ comes before Ag+ on the standard potentials given on the data sheet, it must be undergoing oxidation and therefore, the equation given on the data sheet would need to be reversed.
Basically;
Fe3+ + e- -----> Fe2+ (This needs to be reversed because undergoing oxidation)
Therefore becomes:
Fe2+ -----> Fe3+ + e-
Reduction equation is; Ag + e- -----> Ag(s)
Overall, the electrons cross off to give you:
Fe2+ (aq) +Ag+ (aq) ------------> Fe3+ (aq) +Ag(s)
Hope I've helped