I tried the Vivaldi version of this a few months ago and it unfortunately does not meet the feature set of Tree Style Tabs. It isn't a worthwhile alternative, for me.
What's the story on inserting data into Cayley? I think every single code example I have seen on it only shows traversing graphs with it.
Also, if you don't mind me asking, how does it not being a property graph affect modelling your data and queries? At a glance it seems that queries would get significantly more complex if you wish to take several properties of a vertex into account.