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