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