How would you explain green to someone who has no concept of colour? The basic otherness of neurodiversity is simultaneously the defining characteristic, overarching difficulty, and blocker to understanding by neurotypicals. I very much like these ideas on how to make the effect of this affliction relatable to others.
You might also ask them to play this little game (takes 5 mins) about a little adhdinosaur who is really, really trying to do his best. However, as good as this game is, it may be too whimsical for its own good as people might not take it serious. Yes, the idea is to give the player a sense of frustration, but there's not really anything there to make them think deeply about why and how this affects people like us. But at least, the game page links to a "making of" presentation by the author, as well as other games and resources for/by neurodiverse folk.