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