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