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