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