The connections start with his name. Simon is a reference to Simon Peter from the Bible, who was one of the disciples. He has a conversation with the pig's head, the "Lord of the Flies", which is another name for Beezlebub, which is another name for Satan.
Simon, like Christ, is portrayed as kind, compassionate, and peaceful. Also, early in the story, he is shown as a provider of food - providing fruit in the way that Christ provided bread:
"Then, amid the roar of bees in the afternoon sunlight, Simon found for the fruit they could not reach... passed them back down to the endless, outstretched hands."
Like Christ, Simon is a prophet, who gains insight into what the beast of the island really is. When he tries to bring this knowledge to the people, he is slaughtered by his own kind - in the way that Christ was crucified.
Like Christ, Simon is an innocent, but is brutally killed by the hunters. He also seems to have a keen sense of insight that is almost prophetic in nature. He alone understands that "the beast is only us"--meaning that the uncivilized and uncontrolled behavior of the boys will be what destroys them.
The scene when Simon is "tempted" by the Lord of the Flies (the pig's head on a stick) can also be compared to the passage when Christ is temped by Satan in the Gospel of Matthew, chapter 4. The Lord of the Flies is a reference to "Beelzebub," a synonym for Satan.