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