First, you need to go east of Thais and dig the hole I marked below with white circle. Monsters on the way are quite easy (Trolls, Trolls Champions, Orcs, Orcs Warriors, Rotworms), so it shouldn't be a problem to reach this place even for lower level players.
Next, follow this way:
Then, use Exani hur up spell in this place and direction:
And the room with the Utevo Lux scroll will be on the left side:
I used this article created by TibiaRoyal but this fansite no longer exists thus the link is broken.