As FPM, said anything below the shocking level for your cya level is considered safe to swim. So, if the pool looks clear (and only if it looks clear, since if it isn't clear you probably shouldn't have swimmers in it), on the day of the swimming guests, just don't add any chlorine in the morning and wait till the end of the day to bring it up to your shock level.
However, if you are having swim guests for multiple days, or if the pool is not clear, then you really need to finish the shocking process before the swimming. When are your guests coming and for how long?
If you still have a day or more until swimming, you can hit it hard with the Mustard Algae level (44 ppm FC for 80 ppm cya per poolcalculator.com), it is harder on equipment, and will likely use a little more chlorine, but will speed up the clearing process. What pool surface do you have?
Then, if you do not have enough sun/time to drop the chlorine level nomally, you can consider something like odium thiosulfate to reduce the FC level quickly. It usually can be purchased at a pool store. FYI, this approach is not generally suggested on tfp because it is extra stuff that is not normally needed for a trouble free pool.