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