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