The Sentence Diagram Generator will visually represent the sentence "Martha ate lunch at Chili’s, her favorite restaurant." as follows:

          +------------------+
          |      ate         |
          +------------------+
          |                  |
      +---+---+          +---+---+
      |  Martha |        |  lunch  |
      +---------+        +---------+
                          |
                          +------------------+
                          |      at          |
                          +------------------+
                          |                  |
                      +---+---+          +---+---+
                      |  Chili’s |      |  her    |
                      +---------+        +---------+
                                          |
                                          +------------------+
                                          | favorite         |
                                          +------------------+
                                          |                  |
                                      +---+---+          +---+---+
                                      | restaurant |      |
                                      +------------+      |
                                                          |

This diagram illustrates the grammatical structure of the sentence, showing the subject, verb, object, and prepositional phrases.