Apparently, some of the latest versions of LibreOffice productivity suite support formats from Microsoft Visio, including diagram files (.vsd). So you can try to download LibreOffice and use the Draw program to produce a .odg drawing based on the Visio .vsd file.
Convert Microsoft Visio diagram document to OpenDocument drawing.
We have found 2 software records in our database eligible for .vsd to .odg file format conversion.
Multiplatform software - convert vsd to odg on any platform
A vector graphics editor
Convert from vsd 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 vsd to odg. 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.
Graphic and diagram software from LibreOffice suite