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