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