Which way is the Kronus Expanse in relation to the Calixis Sector?

Almost directly rimward, if I'm not mistaken.

That's the impression I got too.

It is hte most westren border of Calixis, and maybe a bit north too. The map is somewhere on the website where it shows the Calixis sector still on it. Not the new technical map they put up, but rather the traditional fancy one.

My impression is that you can see what is called 'The Maw' on both maps. On the Koronus Expanse map it is on the right between the two nebulae (The Hermitage and The Temple are inbetween) and on the Calixis Sector map it is on the utmost left side where The Halo Stars is written between two blurry nebulae (orange and green).