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)(15,17)(16,26)(18,22)(19,20)(21,27)(23,25)(24,28) involution — undirected(5,6)(7,10)(8,9)(11,12)(13,14,18,22)(15,23,21,28)(16,20,19,26)(17,24,27,25)(2,4)(13,15,18,21)(14,17,22,27)(16,25,19,24)(20,28,26,23)(5,7,8,11)(6,10,9,12)(13,16,18,19)(14,20,22,26)(15,24,21,25)(17,23,27,28)(6,9)(10,12)(13,17)(14,21)(15,22)(16,23)(18,27)(19,28)(20,25)(24,26) 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.