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