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