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