To create a PDF from MacLux Pro on OS-X, use the Print command and choose the Save as PDF... option from the popup menu in the Print dialog.
If you want to have a single PDF rather than one that is broken into pages, use the Page Setup command to set a page size large enough to accommodate the entire plot before exporting a PDF from the print dialog. This may entail creating a custom paper size using the "Manage Custom Sizes" option.