One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,4,3)(5,6)(7,9)(8,10)(11,12)(13,14)(15,22)(16,20)(17,19)(18,23)(21,25)(24,26)(27,28)(2,3)(5,6)(7,11)(8,10)(9,12)(13,15,16,23)(14,18,20,22)(17,24,25,28)(19,27,21,26)(5,7)(6,9)(8,12)(10,11)(14,19)(15,23)(17,25)(18,26)(20,21)(22,27) involution — undirected(1,3,4,2)(7,12)(9,11)(15,23)(18,22)(24,28)(26,27)(6,10)(9,11)(15,23)(18,22)(24,28)(26,27) 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.