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