The entire story of "Animal Farm" can be interpreted as an event of figurative language because the tale is an allegory, or a metaphor that is applied to the story as a whole. "Animal Farm" tells the story of the Russian Revolution, except that Orwell uses animals on a farm as characters instead of actual historical figures. For example, the well-spoken boar named Napoleon represents Stalin, while another young boar, named Snowball, represents Trotsky. In fact, each animal on the farm represents at least one major character in the actual Russian Revolution. The pig, Major, who delivers the opening speech that inspires the rebellion, represents both Marx and Lenin.
In addition to the fact that the animals represent specific people involved in the revolution, the types of animals that represent certain characters or parties are themselves rich in symbolism. For example, the sheep represent the Russian people who, you might say, have had the wool pulled over their eyes. Puns aside, sheep are conventionally referenced as animals that follow blindly -- even to their own demise, and so it makes sense that Orwell takes advantage of this cultural meme, and applies the symbolic attribution.
Once you look past the overarching, symbolic premise of the novel, you can more easily focus on conventional forms of figurative language, such as expressive descriptions, similes and metaphors. Orwell provides examples on nearly every page of the text, though they are sometimes so common that they can be difficult to identify. For example, early in Chapter II the narrator says that Mr. Jones "had been a capable farmer, but of late he had fallen on evil days. He had become much disheartened after losing money in a lawsuit, and had taken to drinking more than was good for him." Taken as concrete language, the phrase "had fallen on evil days" would mean that on evil days, Mr. Jones fell down, which is not at all what the narrator implies.
Orwell also employs a more common form of figurative language throughout the entirety of the text, namely stock metaphors of personification. You can find an example of this in the opening paragraph of the text. The second sentence of the novel reads: "With the ring of light from his lantern dancing from side to side, he lurched across the yard ..." While the phrase is so common you might not consider it overly expressive, to say that the light danced is figurative. It did not dance. It might have flickered or flashed, but to say it danced is to personify the light, as only living things can dance.