I considered centering while developing the diagrams and concluded that centering looking out of place in the jupyter ecosystem. All of the HTML representations from other libraries I have seen are left-justified.

What are the advantages you see for centering the diagram?

I think it's ok being left-justified in the notebook. At today's office hours, I believe the discussion was around having it centered in the documentation showing the visual diagrams.

@ogrisel What do you think?

I think this is just a matter of taste. Since we did not make the change since 3 years, I think this is fine. I think that we should prioritize improving the diagram themselves.