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