A Cayley graph X = Cay(G, S) of group G is said to be normal if R(G), the group ofright multiplications, is normal in AutX. In this paper, by investigating the normality, weclassify 3-valent and 4-valent Cayley graphs of a group of order 4p2, G = <a, b | ap2 = b4 =1,ab = ar), where p>3, r2=-1(modp2), p =1(mod4). In addition we obtain severalinfinite families of non-normal 4-valent Cayley graphs of a group of order 4p2,one of whichis one-regular graph. |