Your best shot or exporting .emm mind maps to PDF format would be to use the original MindMaple software. If you do not have access to it, you will have to use some 3rd party brainstorming tool with support of MindMaple formats.
Convert MindMaple mind map document to Adobe Portable document format.
We have found 2 software records in our database eligible for .emm to .pdf file format conversion.
Microsoft Windows software - convert emm to pdf on Windows
A mind mapping and information organizing tool
Convert from emm file format
The tables with software actions are a good pointer for what a certain program does with various file types and often may give users a good hint how to perform certain file conversion, for example the above-mentioned emm to pdf. However, it is not perfect and sometimes can show results which are not really usable because of how certain programs work with files and the possible conversion is thus actually not possible at all.
Apple macOS / Mac OS X software - convert emm to pdf on OS X
An app for project managing, concept mapping, brainstorming, etc.