Sounds like shock, because of you moving it and repoting it. Some plants don't take kindly to so much change. I have a Caerulea in full sun most of the day and it is fine. I would put it in bright shade to help it recover. Keep the soil moist but not wet, overwatering can be just as bad and wait. Caerulea is supposed to be fairly hardy so I would expect it will recover, give it time.

Don't understand why you potted it in cactus mix - isn't that for slow-growing succulents that don't need rich soil & for fast drainage? Suspect it's not able to draw enough moisture & nutrients from that mix. I grow Blue Bouquet, a hybrid of Caerulea, directly in the ground of clay amended with compost, topsoil & gypsum. It's at least 10 years old now, but when it was younger it definitely needed a good soaking every couple of days or it sulked. (Blue Bouquet has proven root & older cane hardy here in central Virginia zone 7A in an Eastern exposure planted beneath a stone wall.) Also grew another Caerulea hybrid in a pot years ago that spent the warm months outside & the cold ones in. Repotted that every Autumn until it filled a 22" pot. It also had regular heavy potting mix with vermiculite & perlite (no peat or sphagnum).

You might move it temporarily so it only gets morning sun & repot in better soil until it improves. Then it can go back to the sunnier spot as long as it's well watered in the heat. You don't mention what type of pot it's in. If clay, that will deprive it of water as the clay will absorb any that doesn't immediately drain out. Even if the outside of such a pot is glazed, the unglazed interior will soak up water. Or your pot may be another dark material, which may be overheating the roots if exposed to the sun.

So think it's a trouble-shooting challenge.

Here is a link that might be useful: Blue Bouquet