Look at LocalLlama (r/LocalLlama). Will work for you. For graph generation, use CodeLlama or a wizard fine-tune and teach it to use ChartJS.

It seems like it would be split into two layers; the LLM would first plan the presentation based on the user provided prompt and bind it to some kind of template (IE: Title Slide, Big Number, etc) outputting a JSON. Then, take each template and run another LLM call and outputting the details of each slide as another JSON while concurrently running calls to an image creator or image search to fill in the template.