There are two distinct approaches to printing a Z specification that has been prepared using the LATEX mark-up.
Latex requires that your file be named with the .tex suffix. If you used the .z suffix for cadiz, rename the file to have the .tex suffix, as cadiz will accept that too.
Latex can then be run on your Z specification just as for any other document, and the resulting .dvi file printed in the usual way, e.g.
latex filename.tex dvips -f filename.dvi >filename.ps lp filename.ps
Printing via LATEX causes formal paragraphs to be layed out as specified in the mark-up (this is the author's responsibility), and informal paragraphs to be typeset.
Having used cadiz to preview the specification (and perhaps browse it or prove things about it), you will have an output file from troff named with suffix .dit that can be printed in the same way as a specification written using troff mark-up.
MARKUP=latex cadiz -x filename.z grops filename.dit >filename.ps lp filename.ps
Printing via cadiz causes formal paragraphs to be layed out automatically by cadiz's prettyprinter (resulting in consistent layout to which readers can become accustomed, though that layout may not be as an author desires), but informal text between paragraphs is omitted.