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