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