The Office for this feast day:
The hymns for Apostles and Evangelists are sung today, and can be found here. Below is Caravaggio's "The Conversion of St. Paul":
There's another Caravaggio version of this that I like better:
And I really like this one, too, labeled "An illumination depicting the Conversion of Saint Paul from Livre d'Heures d'Étienne Chevalier (c. 1450–1460) by Jean Fouquet."