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)(16,24)(17,19)(18,22)(20,25)(23,27)(26,28)(6,9)(7,11)(13,15,16,22,17,23,25,28)(14,18,20,21,19,26,24,27)(2,4)(5,6)(7,10)(8,9)(11,12)(14,19)(18,26)(20,24)(21,27) involution — undirected(6,9)(10,12)(15,22)(16,25)(18,21)(20,24)(23,28)(26,27) involution — undirected(5,7,8,11)(6,10,9,12)(14,19)(15,23)(20,24)(22,28)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.