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