I’m delighted to report that there is a new plug-in (only in beta, for manual install): “Graph Presets”: GitHub - ycnmhd/obsidian-graph-presets: Markdown-based graph controls.
The plug-in developer has quickly added some improvements that make this really, really useful: Applying a preset to different local graphs without saving it as a snapshot of a note linked to its local graph · Issue #13 · ycnmhd/obsidian-graph-presets · GitHub
Strongly recommended! It allows you to set a hotkey to apply graph settings to any graph, including local graphs.