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)(15,22)(16,18)(17,19)(20,24)(21,26)(23,28)(25,27) involution — undirected(1,2)(3,4)(6,10)(11,12)(13,15,18,24)(14,20,16,22)(17,27,21,23)(19,28,26,25)(5,7,9,8)(6,11,10,12)(13,16,26,21,18,14,19,17)(15,23,28,22,24,27,25,20)(2,4)(5,8,9,7)(6,12,10,11)(13,17,26,16,18,21,19,14)(15,20,28,23,24,22,25,27)(6,10)(11,12)(14,16)(17,21)(20,22)(23,27) 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.