Swing up the wall that leads to checkpoint 6.

Then as you're going up the wall, or when you've flown to slightly above it, grapple back down the wall twice in quick succession.

Do this while facing away from where you want to launch yourself so that you won't accidentally hit a beam.

KEY DETAIL: From my experience, you need at least 560-570 velocity to have enough speed to launch yourself across the map, but the higher the better.

When you angle your camera, you want it to face the general direction of the bottom of the area you want to land, and make sure to grapple a bit away from the wall so that you don't accidentally hit it.

When I'm at the very bottom you can see I have 600+ velocity

Which shoots me to about here on the map