The Sentence Diagram Generator visually represents the sentence "The red dog is running from the cat" as follows:

                +-------------------+
                |       is          |
                +-------------------+
                |                   |
            +-------+          +---------+
            |  dog  |          | running  |
            +-------+          +---------+
            |       |          |         |
        +-------+  |          |         |
        |  red  |  |          |         |
        +-------+  |          |         |
                   |          +---------+
                   |          |   from   |
                   |          +---------+
                   |          |         |
                   |      +-------+    +-----+
                   |      |  the  |    | cat |
                   |      +-------+    +-----+
                   |
                +-------+
                |  The  |
                +-------+

This diagram illustrates the grammatical structure, showing the subject ("The red dog"), the verb ("is running"), and the prepositional phrase ("from the cat").