Save output with colors to HTML/PDF etc
Install ansifilter.
git show \
| delta --no-gitconfig --file-decoration-style blue --hunk-header-decoration-style blue \
| ansifilter --html \
> /tmp/diff.html
Now open /tmp/diff.html in a web browser, print to PDF, etc.
Remove the --no-gitconfig above to use your own delta style, but note that ansifilter does not handle hyperlinks or decoration boxes etc.