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