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