It can be more useful to make your own metaphor that feels very accurate to this child's particular experience, so that the child feels that you really get it, and are helping them to get it.
My 2e kids are dealing with a different set of challenges (not ADHD), but fwiw, we've found DeeDee's advice to work really well. Another thing that has helped us is finding bios of real-life adults who've shared the same challenges (it's also helped me find ways to support my kids by reading about what worked/didn't work in the childhood experiences of successful adults who'd shared the same type of challenges).
I can't comment directly on this since I haven't read it and we're not dealing with ADHD, but fwiw one of my children is dyslexic, and there is a lot of information out there (and books by successful dyslexic adults) that portray the mirror strengths of dyslexics. Looking at mirror strengths has been helpful to a certain extent, but our neuropsych also cautioned about going too overboard on this track (which I know aeh wouldn't!) - our neuropsych's concern was triggered by the concept put forward in some literature that dyslexia is a "gift" because of those mirror strengths, and her concern was that it minimizes the reality that no matter how wonderful those mirror strengths may be, the person is still dealing with a very real challenge.
Best wishes,
polarbear
