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