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