You can draw in Pages but considering Apple has done this before in other applications, it is a pretty rubbish experience.
The Shapes menu on the Toolbar has a wide variety of shapes, all of which are editable. At the bottom of the menu is a pen tool with which you can draw bezier curves. It can do quite a lot but is frustratingly clumsy and annoying. I take pride in making it do anything, but what a waste of time, compared with using a real drawing program.
I'd save a lot tooth enamel and just go to a real third party drawing application and save the work as a pdf to bring into Pages. If you have it, use Adobe Illustrator.
If you don't want to spend that kind of money there are plenty of cheaper alternatives. The best of the crop IMHO is Sketch, available in the App Store, which whilst it doesn't have everything plus the kitchen sink like Illustrator, it has one of the most innovative user interfaces around.

If you still want to use Pages' Drawing Tool I'd keep the map very diagrammatic and minimalist.
Peter