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