One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,4,3)(5,6)(7,11)(8,10)(9,12)(13,14)(15,20)(16,19)(17,21)(18,23)(22,27)(24,25)(26,28)(5,6,8,10)(7,9,12,11)(13,14)(15,20)(16,24)(17,21)(18,23)(19,25)(22,26)(27,28)(5,6)(7,9)(8,10)(11,12)(13,15)(14,18)(16,22)(17,23)(19,26)(20,21)(24,27)(25,28) involution — undirected(5,7,8,12)(6,9,10,11)(13,16)(14,19)(15,22)(17,25)(18,26)(20,27)(21,24)(23,28)(1,3,4,2)(13,15)(14,20)(16,22)(17,23)(18,21)(19,27)(24,26)(25,28)(13,14)(15,18)(16,19)(17,21)(20,23)(22,26)(24,25)(27,28) involution — undirectedA Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.