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