For group presentations with cyclic symmetry, there is a connection between asphericity and the dynamics of the shift automorphism. For the class of groups G n (k, l) described by the cyclic presentations P n (k, l) = (x i : x i x i+k x i+l (i mod n)) and studied extensively by G. Williams and M. Edjvet [12], the shift acts freely on the nonidentity elements of G n (k, l) if and only if the presentation P n (k, l) is combinatorially aspherical in the sense of [6]. The shift has a nonidentity fixed point precisely when G n (k, l) is finite. MSC (2010) 20F05, 20E36.