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