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