Out-of-universe answer: Calculon is whatever the writers want him to be. Characters in Futurama "die" all the time, only to be brought back by cloning, reclaiming their "life force", or whatever.
In-universe answer: Assuming Calculon really is dead (and not just acting), then we can figure out his current state by first considering what happened to Bender when he previously died...
In the episode "Ghost in the Machines", Bender (again) goes to a suicide booth to commit suicide, only to discover that he had previously dated said suicide booth. She kills him for dumping her, and Bender ends up in Limbo with his software having been uploaded to the computational cloud. The Robot Devil then offers Bender a deal to return to his old body. Even though a previous episode "Lethal Inspection" explained that Bender has a faulty back-up unit and can't download into a new robot body, this episode would seem to imply that Bender's limitation has been removed due to the normal course of technological advancement that occurs in robot society (such as when Bender is given an upgrade to be made more compatible with Robot 1-X in the episode "Obsoletely Fabulous").
So, what does this mean for Calculon? Well, Calculon received routine upgrades to his robot body over the course of 1000 years (episode "The Honking"), thus meaning he should also be capable of having his software uploaded to the computational cloud when he dies. He also committed suicide by drinking the food coloring, meaning that he will end up in Limbo just like Bender. However, Calculon had previously made a deal with the Robot Devil for his "unholy acting talent", and although the Robot Devil collected on that bargain by asking Calculon to give up his ears (episode "The Devil's Hands Are Idle Playthings"), making a deal with the Robot Devil is likely considered a sin in the eyes of the Robot Church. Calculon would therefore almost certainly end up in Robot Hell, the property of the Robot Devil, like all the other sinner units.
Therefore, the in-universe answer is like the out-of-universe answer, but replace "writers" with "Robot Devil": Calculon is whatever the Robot Devil wants him to be. If the Robot Devil wants to give him a chance to return to his body (like he gave Bender) then we will see Calculon again.