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