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