If the branch feed to the receptacles first then all that's needed is 2 conductors routed to the switch. Likely it would be a 14/2 with the white marked black as the constant feed and the black as the switched conductor going back to the receptacle *S*
I believe the branch feed is 14/2 ( black and white ) comes from the panel into the switch box.
From there a 14/3 feeds the receptacles ...
black -- connected to bottom half of receptacle *S* which is constant power. This also feeds the other receptacles downstream on the branch.
Red -- connected at the switch and from there the top half of receptacle *S* providing switched power .
It's the presence of the white neutrals in the switch box location that points to this and is the most common wiring scheme I see.
However, an exception could be the branch feed does go to the receptacles first and then is extended somewhere else . In which case that would be why explain the 5 conductors inside the switch box.