No simple swagger to markdown converter currently exists in python. In order not to introduce java dependencies from popular projects when doing a python project, I created a very simple converter.
./swagger2md.py swagger.json swagger.md
Then you can use a md to pdf converter like pandoc to produce a pdf file !
apt-get install pandoc texlive-latex-recommended texlive-fonts-recommended
pandoc -s swagger.md -o swagger.pdf
If you want to style using md -> html converter
apt install wkhtmltopdf
pandoc -t html5 -c swagger.css --toc -s swagger.md -o swagger.pdf
An example swagger.css is included, modify it if you need to !