The Sentence Diagram Generator visually represents the sentence "To cruise across the ocean would be my ideal vacation" as follows:

                +---------------------+
                |        would        |
                +---------------------+
                          |
                          |
                +---------------------+
                |        be           |
                +---------------------+
                          |
                          |
                +---------------------+
                |     my ideal        |
                |      vacation       |
                +---------------------+
                          |
                          |
                +---------------------+
                |     To cruise       |
                +---------------------+
                          |
                          |
                +---------------------+
                |      across         |
                +---------------------+
                          |
                          |
                +---------------------+
                |      the ocean      |
                +---------------------+

This diagram illustrates the main components of the sentence, including the infinitive phrase "To cruise across the ocean" as the subject, and "would be my ideal vacation" as the predicate.