Having only taken one syntax class for fun in college, I find this pretty impressive. Generating syntax trees was never a trivial task for me (but I was just a CS major who needed a credit). Slightly related, but I have also never had ChatGPT successfully generate ASCII art, even with extensive conversation.
Yeah, I think it would be very challenging for most people. It did considerably better with Graphviz than with ASCII art, but it still had trouble with the transition from a perfectly correct and highly nuanced verbal grammatical analysis to Graphviz. I think this is pretty convincing evidence against ChuckMcM's implicit position. It's weaker evidence against mschuster91's explicit position because parsing is something computers have been doing for a long time, so it doesn't imply any new capabilities.
I'm pretty sure there are part-of-speech tagging parsers using fairly shallow statistics that could also have produced an equivalently good sentence diagram. https://corenlp.run/ seems to produce a correct parse, though in a different format.
If you ask it to draw a dinosaur it does an okay brontosaurs.
Asking for a Tyrannosaurus Rex gives you more or less the same brontosaurs: