  We numerically investigate Andreev reflection in a graphene ring with one
normal conducting and one superconducting lead by solving the Bogoliubov--de
Gennes equation within the Landauer-B\"uttiker formalism. By tuning chemical
potential and bias voltage, it is possible to switch between regimes where
electron and hole originate from the same band (retroconfiguration) or from
different bands (specular configuration) of the graphene dispersion,
respectively. We find that the dominant contributions to the Aharonov-Bohm
conductance oscillations in the subgap transport are of period $h/2e$ in
retroconfiguration and of period $h/e$ in specular configuration, confirming
the predictions obtained from a qualitative analysis of interfering scattering
paths. Because of the robustness against disorder and moderate changes to the
system, this provides a clear signature to distinguish both types of Andreev
reflection processes in graphene.
