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