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