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