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