Considering the omnipresence of God, a good question to ask would be, "How could God not be around Satan?" Psalm 139 as well as other places describe how God is everywhere and fills heaven and earth.
There is, however, a distinction in the impact of His presence. For instance, if the police show up while a crime is taking place, how can they tell the difference between the criminal and the victim? The answer, of course, is that the criminal runs in fear, while the victim is relieved. Two people with two very different responses to the presence of the police.
Thus, Adam and Eve hide from God, Cain tries to excuse his responsibility, many people try their best to convince themselves that God does not exist. Adam said it well, "I heard You in the garden, and I was afraid, because I was naked (shame), so I hid."
Two people can be in the same room, and a married couple can even sleep in the same bed, but they can be completely isolated from each other--not physically, but emotionally and spiritually. So, it's possible for God and Satan to be in close proximity, yet be completely isolated.
So, God's presence does fill heaven and earth, but the response to His presence varies greatly. The response can be joy or terror, acceptance or condemnation, communion or isolation.