I don’t use such a machine myself, but those are tools which I would turn to if I had :
The first one is just a library (i.e. building blocks), while the second looks more like a complete solution - based on Linux’ most used vector software Inkscape.
It’s more for CYOA-like games, but Twine is pretty good and has a graph-like editor. Of course, if you want to do anything more complicated than “if (choice) go (page)”, you might need some code. But for the basics it works without.