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