The selected answer may have been right in the past, but it no longer is in the versions I've tried (ffmpeg version 2021-12-09-git-b9f4c1231f-full_build-www.gyan.dev + ffmpeg version 2023-04-10-git-b18a9c2971-full_build-www.gyan.dev).
I'm presuming you'll be able to use seeking with the waveform imaging... otherwise you'll need to cut the sound clip first.
The above portion of the selected answer IS correct, however. Seeking does not work with showwavespic. This should probably be submitted as a bug to ffmpeg.
The command below does work and hackily pipes the output of one ffmpeg command (one for splitting) to another (one for the waveform creation).
It assumes an input video with aac audio (otherwise you will need to change the -f paramater in the first command) and is set to overwrite the created output.png if it exists (-y in the second command) rather than fail in that case.
ffmpeg -i inputfile.mp4 -ss 1:11 -t 3 -vn -acodec copy -f adts - | ffmpeg -i - -y -filter_complex "compand,showwavespic=s=800x400" output.png
Another option is found in the man pages https://trac.ffmpeg.org/wiki/Waveform#UsingGnuplot but I haven't gotten around to trying that yet.