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