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