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