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