Here's an example of how to position nodes for this shape:


Notice I have only placed them in horizontal and vertical positions (except where they touch the boundary of the circle). This encourages much smoother curves.
Whilst I positioned the nodes by referring to the drawing, a smarter person might have noticed the rough pattern they formed and created a best-fit curve to more accurately guide the positioning of those nodes.
In early versions my lines spilled outside of the sphere and I used a circle to trim it back. Also the Orange object is an exact copy of the pink object, only flipped horizontally.