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