This guide is an overview of the Santa Claus event that was added with patch 1.2.0, including the locations of the ten presents that need to be found, the location of Santa, and what the reward of the quest is.
Basic Event Overview
Present (and Santa) Locations
1. Just east of the marker at the fields.
Marker 9
2. Just north above the marker. Accessible by going to the field with the tractor and carefully walking on the ledge.
3. Northeast of the marker across the bridge.
Marker 7
4. South of the marker in the canyon.
5. Head along the southeastern path until you reach the sign pointing to the Canyon, Yellowfields, and Turtle Rock. Head towards Yellowfields.
Yellowfields (Campsite)
6. Follow the river that is on the east side of the camp north. When you reach the bridge, the present should be northeast of it near a drop off.
7. Follow the river that is on the east side of the camp south on the opposite side of the river that Yellowfields is on. As you head south you will jump up a few ledges to where the present is.
Abandoned Mill (Campsite)
8. The water mill at the Abandoned Mill camp has the present on its deck.
Yellowfields Town
9. Take the western path from Yellowfields up to the Yellowfields Town. There is a bridge you can cross on the second lowest section of the town where the present is resting on the bench.
10. This one took me the longest to find. Go to the highest section of the Yellowfields Town, then head to the barrels at the end of the path. Climb up them so you can jump onto the roof of the house they are next to. You can then walk across the roofs of the houses to where the present is on the chimney of a house.
Santa: Sitting on one of the benches in the Yellowfields Town.
Quest Rewards
Thanks to sanddall-asy for his great guide, all credit to his effort. you can also read the original guide from Steam Community. enjoy the game.