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