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)(13,14,16,20,17,18,23,25)(15,19,22,26,21,24,27,28)(5,7,10,6)(8,11,9,12)(15,21)(19,24)(22,27)(26,28)(2,4)(15,21)(19,24)(22,27)(26,28) involution — undirected(5,8,10,9)(6,11,7,12)(14,18)(15,21)(20,25)(22,27)(5,9,10,8)(6,11,7,12)(13,15,16,22,17,21,23,27)(14,19,20,26,18,24,25,28)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.