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