The Datacron is located down the beach from the flight point. There is a sloping path down the to the beach, then just continue to head south. Eventually you'll round an outjut of the cliff and will see the beam glowing upward of the Datacron behind some rocks just off to your left.
Map Pictures Follow:
|World view of the Presence Datacron on Ord Mantel|
|Actual view of the Presence Datacron on Ord Mantel|