If you truly need diagramming software without installation, consider these :
You get the full power of the Visio desktop app without leaving traces on the host computer. microsoft visio portable
Draw.io is arguably the best alternative to Microsoft Visio. It is completely free, open-source, and has a dedicated, official portable version. If you truly need diagramming software without installation,
Any file labeled "Microsoft Visio Portable" found on the internet is an unofficial package created using third-party virtualization tools like VMware ThinApp, Cameyo, or Turbo.net. The Dangerous Risks of Unofficial Portable Versions and has a dedicated