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