Two vertices u and v of a graph Γ are strucuturally equivalent if and only if the transposition (u v) is in Aut(Γ), the automorphism group of Γ. Some properties of structural equivalence and the group of vertex permutations generated by the transpositions in Aut(Γ) are discussed, along with the prime graphs of these groups. The notion of structural equivalence is used to develop a way of reconfiguring graphs into what are called their complete skeletons, which is closely related to compression graphs. Finally, the complete skeleton of a graph Γ, denoted Ω(Γ), is used to find a formula for rank(I + A(Γ)), which is helpful for determining the multiplicity of the -1 eigenvalue of Γ.