No, unfortunately, it is not possible to create multiple Travel Book versions for one trip at the same time in one account. There's always only one Travel Book version per trip. Once you make changes and save them, that becomes the current version. It's also not possible to duplicate a trip or Travel Book to work around this. 

That said, you can still end up with multiple Travel Book versions from the same trip if you have one or more trip buddies. Each buddy can work on their own Travel Book simultaneously. However, you only have access to the Travel Book in your own account.

Note that if you or any Travel Buddy makes a change to the trip while you are creating a Travel Book this will be reflected in the Travel Book. Please read this article for more information: Travel books for Travel buddies