There appear to be very few surviving depictions in ancient art of how papyrus rolls were actually used in daily life. One that might be more symbolic and ceremonial than "realistic" in our sense is the ivory diptych of Rufius Probianus, which celebrates his installation in Rome as Vicarius urbis Romae. According to Berger's Encyclopedic Dictionary of Roman Law, Vol. 43, 764, the Vicarius in urbe (Roma) was the "head of the administration of the southern part of the dioecesis Italia. . . ."
In the diptych Probianus appears with his right hand lifted in an oratorical gesture to indicate that he is either speaking or has the right to speak. However, from the perspective of book history what may be more significant about this diptych is not the large seated depiction of Probianus, but the depiction to his left and right of secretaries recording his speech on polyptica, or groups of wax tablets tied together like codices, and of orators in the panel below him pointing with their right hands while they hold open papyrus rolls in their left hand with their fingers used as place markers. This shows how orators held papyrus rolls open for reference while they spoke.
A clearer image of the Probianus diptych than that in Wikipedia commons appears in Wright, The Roman Vergil and the Origins of Medieval Book Design (2001) 8. Quality images of both covers, each subtly different, with commentary are reproduced in Weitzmann (ed) Age of Spirituality. Late Antique and Early Christian Art, Third to Seventh Century (1979) no. 53.
The diptych is preserved in the Staatsbibliothek, Preussischer Kulturbesitz, Berlin, Ms. theol. lat. fol. 323.