Dear,
As far as I know, In POM Campaign strategy we can set only one calling allowable time in parameters Min Contact Time & Max Contact Time. But there is requirement to set calling allowable time for weekdays from 10 Am to 8 pm am and for weekends from 4pm to 8 pm.
Kindly advice on How can we achieve this?

It may require 2 campaigns and 2 strategies, one for the weekdays and on for the weekend.
You might look into adjusting the Guard Times if these restrictions are more global and you want all campaigns to maintain them.
Another option would be to look into the Rule Editor and create some restrictions to prevent calls outside the desired times.
Just some things to think about.

In one strategy I added 2 Restricts, one with Friday and second with Saturday with Time in Exception. Seems working fine.