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