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