Save it as a PDF file (with File – Save PDF). Then use a free reader like Acrobat Reader or Sumatra PDF, that have full Print and Print Preview support. You may send it to a printer, fax it, email it etc. PDF page format and margins can be adjusted from the toolbar at the bottom of your screen. Large diagrams are cut into separate pages.
If you want just one large diagram, with no pages, to send to a plotter, save it rather as an image (with File – Save Image) and use one of the many free image tools to print it as it is.
You can also copy it in the clipboard (with Edit – Copy) and paste it into another document, such as Word, then use that tool’s print support.
There is no direct command for that only those options provided.. You can save or paste it on its recommended tool there you can see the print option. Soon for sure they are working on that direct print from the program itself.