The Sentence Diagram Generator visually represents the sentence "The teacher's needed supplies are in the office" by breaking it down into its grammatical components. The subject "The teacher's needed supplies" is diagrammed on the left, with "supplies" as the main noun, "needed" as an adjective modifying "supplies," and "The teacher's" indicating possession. The verb "are" connects to the subject, while the prepositional phrase "in the office" is shown on the right, with "in" as the preposition and "the office" as the object of the preposition.