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