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