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)(23,28)(24,25) involution — undirected(5,7)(6,9)(8,12)(10,11)(13,14)(15,23)(16,20)(17,21)(18,26)(19,25)(22,28)(24,27) involution — undirected(1,2,3,4)(13,15,16,24,17,22,18,25)(14,19,26,28,21,27,20,23)(6,10)(9,11)(13,16,17,18)(14,20,21,26)(15,24,22,25)(19,23,27,28)(7,12)(9,11)(13,15,16,24,17,22,18,25)(14,19,26,28,21,27,20,23)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.