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