I had coffee today with Father Gary Selin, priest in residence at my parish (St John the Beloved in McLean, VA) who pointed out that for St Ignatius of Antioch, the deacons are directly associated with the person of Jesus Christ and not the presbyters:

“In like manner let all men respect the deacons as Jesus Christ, even as they should respect the bishop as being a type of the Father and the presbyters as the council of God and as the college of Apostles. Apart from these there is not even the name of a church.”

– Epistle of Ignatius to the Trallesians 3:1

Thus the symbology of the Ignatian hierarchy is:

Bishop – God the Father
Presbyters – Apostolic College
Deacon – Jesus Christ

I assume that this is because the bishop himself was the chief and only celebrant and the deacons were the only other ministers present at the altar assisting the bishop. In this time, only the bishop and his deacon(s) would be standing at the altar. Thus, only the bishop and deacon would be associated with Persons of the Godhead.