  Let $k \geq 1$ be an integer and $n=3k-1$. Let $\mathbb{Z}_n$ denote the
additive group of integers modulo $n$ and let $C$ be the subset of
$\mathbb{Z}_n$ consisting of the elements congruent to 1 modulo 3.
  The Cayley graph $Cay(\mathbb{Z}_n; C)$ is known as the Andr$\acute{a}$sfai
graph And($k$). In this note, we determine the automorphism group of this
graph. We will show that $Aut(And(k))$ is isomorphic with the dihedral group
$\mathbb{D}_{2n}$.

Combinatorics