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)(13,14,17,22)(15,23,25,19)(16,20,18,21)(24,27,26,28)(2,3)(6,10)(11,12)(13,15)(14,19)(16,24)(17,25)(18,26)(20,28)(21,27)(22,23) involution — undirected(1,2,4,3)(5,7,9,8)(6,11,10,12)(1,3,4,2)(5,8,9,7)(6,12,10,11)(13,16)(14,20)(17,18)(21,22)(24,26)(27,28)(6,10)(11,12)(13,16,17,18)(14,21,22,20)(15,24,25,26)(19,27,23,28)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.