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