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