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)(13,14,17,22,18,21,19,15)(16,24,27,23,26,20,28,25)(5,6)(7,11)(8,10)(9,12)(13,15)(14,19)(16,25)(17,21)(18,22)(20,27)(23,26)(24,28) involution — undirected(2,4)(5,7)(6,9)(8,12)(10,11)(13,16,18,26)(14,20,21,24)(15,23,22,25)(17,27,19,28)(7,12)(9,11)(13,14,19,15,18,21,17,22)(16,24,28,25,26,20,27,23)(6,10)(9,11)(14,21)(15,22)(16,26)(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.