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