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)(13,14,18,21)(15,22,23,28)(16,19,25,24)(17,26,27,20)(2,4)(5,7)(6,9)(8,11)(10,12) involution — undirected(6,10)(7,11)(13,15,17,24,18,23,27,19)(14,16,20,22,21,25,26,28)(7,11)(9,12)(13,16)(14,19)(15,20)(17,22)(18,25)(21,24)(23,26)(27,28) involution — undirected(15,23)(16,25)(19,24)(22,28) 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.