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