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