There are definitely plenty of symbols. Don't forget the irony as well. Irony is important! There are plenty of examples of irony, such as Fortunado and Montresor's names, the crest and motto, Fortunado's toast to the dead, and Montresor's "rest in peace" at the end.
One of the most obvious is the symbolism of the place Montresor brings his victim. Think of the description of the place: the palazzo of the Montresors with its many rooms, the archway that leads to the ‘‘long and winding staircase’’ down to the catacombs, the damp and dark passageway hanging with moss and dripping moisture, the piles of bones, the flaming torches that flicker and fade, and the "clanking'' and "furious vibrations of the chain'' that Montresor uses to bind Fortunato to the wall. The overall atmosphere is one of brooding and horror--which foreshadow the ending of the story--Fortunato's murder. His very name is symbolic...he isn't very fortunate, is he?
Figurative language is language that has meaning beyond its literal sense, or language that goes beyond its literal meaning to achieve special effect (www.dictionary.com). Types of figurative language include symbolism, personification, alliteration, and metaphor. I would suggest trying to locate examples of one or more of these in the story. You can find information about these literary terms here at eNotes or at www.dictionary.com.
Also, check out the eNotes on the story at this link: