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