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