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