E. cyanognathus likes it fairly warm (75-85) and DEFINITELY with enough substrate to burrow in and a full waterdish. Also, I'm not one to advocate high humidity, but this species definitely does better when it's not too dry. The best solution is good ventilation with daily or bi-daily misting in addition to the dish.
E. cyanognathus is an awesome species!! Mine is a very aggressive feeder. They do like the humidity up a little, not swampy but a little moist. This species is an obligate fossorial burrower. Mine spent it's first few weeks with me acting like an arboreal, always at the top of it's enclosure, but has now settled down and has a nice little burrow. One word of caution, these suckers move like greased lightning so be careful!! I had a Xenethsis about 8 years ago, it is also a very cool spider but spiderlings aren't very easy to come by and adults and juvies are pricey.