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