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)(16,24)(17,19)(18,27)(20,23)(22,26)(25,28) involution — undirected(1,2)(3,4)(6,9)(7,11)(14,19)(15,16)(22,27)(23,25) involution — undirected(2,4)(13,15,17,16)(14,20,19,28)(18,25,26,23)(21,22,24,27)(6,9)(10,12)(13,16,17,15)(14,21,19,24)(18,25,26,23)(20,22,28,27)(2,4)(5,7,8,11)(6,10,9,12)(15,16)(20,28)(21,24)(23,25)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.