As long as they dont drive a construction lift on it, they can start framing within a few days.. (80% strength after 3 days air dry). I would worry more about scuffing the finished surface and wait a couple days, but the slab can handle framing loads the next day, assuming it is standard framing practices, and no concentrated load points..
28 days is considered fully cured..

Thank you Rollie.....I do have three 8x8 posts that will be supporting a long beam (I prattle about this on other threads to no end)...I suppose those 8x8 posts (sitting on concrete footing pads) might qualify as "concentrated load points".... any guidence as to how long we should wait on placing those 8x8's?

Thanks again.

realistically, by the time they get the forms stripped the next day an\d the control joints sawed in, youll be fine. Any longer wait than 24 hours to saw the control joints, and they become cosmetic, as the concrete has already decided where it wants to crack at.

A post and beam structure with many point loads will have a different foundation than a stick built structure with a slab and perimeter foundation that supports the stick built walls. It sounds as though your foundation is incorrectly designed for the type of structure that you intend to build. Your building department actually issued you a permit for this?

There are only three posts....they will sit on large concrete footings. Should the footings be elsewhere? Perhaps outside the building, down by the toolshed?

5" concrete slab on grade are only for uniform spread load at grade, ie vehicle load, work benches, storage etc. The maximum loading you can load the slab on grade depends on soil bearing and reinforcement placed inside the slab.
Framing cannot be placed on the 5" slab on grade. All load bearing framing structure must be on strip or pad footings. Perimeter wall framing can be built on strip footings or slab thickening of the slab on grade.
Post point loads must be on pad footings, and the size "large concrete footings" will not fly here. Pad footing must be sized correctly to avoid footing failure and soil bearing failure. The size depends on the load being supported and soil bearing at YOUR LOT.
Pad footings need to be where the post at designed to be at. You cannot just relocate them along with your post, and change the whole framing layout.