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