Good question. I would imagine that if you're doing a complete bed makeover and adding shrubs it would be a job best accomplished in the fall (once we get some regular rain).
I don't see any reason why you couldn't transplant salvias now except they'd be happier if they weren't blooming when they got their roots disturbed.
Are these the big perennial salvia?
My pineapple salvia still hasn't started blooming.
If yours are blooming you could take cuttings now in case what you move later doesn't take.

Thanks Dottie. Most of the salvia are still blooming. My pineapple (in another bed) has not started blooming yet either. The salvia bed that I am speaking of has a large mix of salvia including many greggiis, guaranitica, microphylla as well as others. I would like to wait till a bit later possibly November to transplant them. Adele

Adele, knowing that salvia can be murdered by wet turned to ice, I'd put a tall stake now in the middle of each clump you plan to move. That will give you something to tie the stalks to and then not clip them back until after frost next spring. Clipping them back before winter is not advised unless you plan to cover them with an inverted pot to keep the rain out of the open stalks. Help the roots to grow toward the moisture.

Adele, I would think you could transplant the hardier species like nemerosa and superba this fall, but I'd wait until spring to transplant the greggiis and microphyllas. If you do have to move them now, take a cutting to overwinter just in case you lose them. Guaranitica is pretty tough any way you look at it -- if you transplant and lose 'Black and Blue' there are about a million of us who can restock you in the spring.