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