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