“…In 1983, the second author 22 asked for which positive integers n there exists a non‐Cayley vertex‐transitive graph on n vertices. Several articles directly or indirectly related to this subject (see 1, 2, 6, 13, 17, 19, 23–27, 29, 30, 32, 33, 36, 38, 39, 44for some of the relevant references), have appeared in the literature, answering this question for particular positive integers. For example, in 23 it is proved that every vertex‐transitive graph of order p k , where p is an odd prime and k ≤3, is a Cayley graph.…”