The Sentence Diagram Generator visually represents the grammatical structure of the sentence: "Tom did nothing but whistle softly through his teeth in an annoying way."

1. Subject: Tom
2. Predicate: did nothing but whistle softly through his teeth in an annoying way
   • Main Verb: did
   • Direct Object: nothing
   • Conjunction: but
   • Infinitive Phrase: whistle softly through his teeth in an annoying way
     • Verb: whistle
     • Adverb: softly
     • Prepositional Phrase: through his teeth
       • Preposition: through
       • Object of the Preposition: teeth
       • Possessive Pronoun: his
     • Prepositional Phrase: in an annoying way
       • Preposition: in
       • Article: an
       • Adjective: annoying
       • Noun: way

This structure can be visually represented using the Sentence Diagram Generator, allowing for a clear understanding of the relationships between the components of the sentence.