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