What's a simple solution to have 2 NEMA 14-30 receptacles and switch power between them?
You could use a double throw switch.



Other materials required are just commonly available residential wiring supplies. Enclosures or boxes, wire, conduit, etc. Exactly what you use is unique to your situation and difficult to speculate about.

Update:
Do note this is not the cheapest of devices. As noted by longneck, running a new circuit may be cheaper. This would be quite true unless the panel is a fair distance from the outlets. Now that we have more detail about the intended use, running a new circuit as suggested by Michael Karas is the only reasonable solution. You do not want to be in a position where you cannot charge your car because you need to dry your clothes, or vice versa. You spent good money on a nice electric vehicle, you deserve to have a proper charging setup for it.

This is so important that in the off chance your service cannot handle the additional load, you should seriously consider what's involved in upgrading the service. There will be additional benefits to this beyond being able to charge your car when you need to.