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