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