Using normal water pressure from your garden hose it should take around 9 hours to fill the swimming pool up fully.
When I first fill my swimming pool up that is also 5000 gallons I start filling the swimming pool up before I go to bed and by the time I wake up in the morning which is 9 hours later it's full.
But you could also start early in the day and then continue to fill the swimming pool while you're home.
If your water pressure is a bit lower it may take as long as 20 hours to fill the 5000 gallon swimming pool but usually it can be filled in 9 to 10 hours.