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