Yes, Salviias in general respond well to pruning. I tend to cut mine back a few inches after each flush of bloom to help keep them full. You should prune them hard in late winter, cutting back to one-third by one-half, and can do so again in late summer, even if it's still blooming. It may look stubby for a bit but should flush out with green growth immediately, followed by new blooms. In between those hard cuts, whenever the blooms seem a little tired, give them a light trim-just the top couple of inches-to refresh them.