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