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