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