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