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