Here’s a quick thought on one of the symbolic meanings of baptism.
In Mormonism, water can symbolize evil and the domain of the devil. It can also symbolize mortality. Similarly, for the ancient Hebrews, water symbolized chaos and disorder. Genesis is the account of God subduing the primordial waters of chaos and creating order and life out of them.
To my knowledge, none of the baptismal scriptures explicitly refer to either of these symbolisms. But the scriptures do explicitly describe baptism as rebirth, as participation in Christ’s death and resurrection, and as the death of the old wicked man and the rebirth of the new man of God. The water symbolisms fit with those descriptions of baptism.
In one way of looking at it, the baptism ceremony recapitulates the plan of salvation (like the endowment also does). By the power of God, and with our consent, we go into a world of sin and mortality. Our fall–our immersion–is complete. But God reaches down and lifts us back up into His presence.
In another way, we totally submit our old sinful self to chaos and disintegration. Out of this chaos God makes a new order of creation–our new self.