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