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