For full portability, subscribe to Visio Plan 1 ($5/user/month) or Plan 2 ($15/user/month). Then use the web app from any computer, or install the desktop app (which leaves no registry traces if you use Microsoft’s own portable workspace tool).
There is no legal way. Consider purchasing a low-cost perpetual license from a reseller (e.g., Visio Standard 2021 for ~$280) or using a subscription for one month ($15) and exporting all diagrams to draw.io format before canceling. download microsoft visio portable free
A portable application is a software program that can be run from a portable storage device, such as a USB drive, without needing to be installed on the local computer. This means that you can carry your applications with you and use them on any computer, making it highly convenient for users who work across multiple locations. For full portability, subscribe to Visio Plan 1