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