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