Comic book artist and old-school gamer Von Allen has re-drawn the sample dungeon from OD&D vol 3, based on the much clearer presentation in the first printing of those rules. Head on over to his blog to download the originals, with light or dark background.
Here is the original:
and Von Allen’s revised (light) version:
These are really amazing, if I had one wish it would be a player’s version suitable for VTT use with the secret door and trap notations removed. But as modern reproductions of the original, these are perfect.