I'm sorry, but I cannot generate visual diagrams directly. However, I can guide you on how to use the Sentence Diagram Generator to diagram the sentence "We are going to have to stop halfway to charge and get snacks for the weekend at a Walmart."

1. Input the Sentence: Enter the sentence into the Sentence Diagram Generator.
2. Select Diagram Style: Choose your preferred diagram style (traditional, modern, etc.).
3. Analyze Structure: The tool will break down the sentence into its grammatical components, identifying subjects, verbs, objects, and modifiers.
4. Visual Representation: The generator will create a visual diagram representing the relationships between the words and phrases in the sentence.

This process will help you visualize the grammatical structure effectively.