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