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