Bad news all around:
- There's no Simple XML setting.
- I looked at the element on the page (in Chrome, right-click and choose Inspect), and the text is not there so you can't add CSS to change the display from hidden to visible.
- I looked at the javascript code and realized it's not an easy change either. SVGs don't do text wrapping by default, so those labels are overlaid onto the grid separately. The problem is that their position is calculated based on the "zoomed in" layout, so both the positions and the sizing would be wrong.
It's technically possible to do it, but you'd need to make non-trivial modifications to the visualization logic. Sorry for the bad news; I was hoping to do the same thing.