I had the same issue an just figured it out. If you look towards the bottom left of the editor view, there are three icons: 'Show/Hide Automation Lanes', 'Add Automation Lane' and 'Remove Automation Lane'.
If you click 'Add Automation Lane' (the Plus icon), you'll have the velocity edit (also, as a side note I also figured out that while this defaulted to percentage values, right clicking on the percentage view allows you to change this to the note velocity - but you may already know this)
I'm going to explore further and see if it's possible to set default config for the automation lane to always be there, like in Studio One 4