One vertex per element, one color per generator, with an edge from x to x·s.
(9,10)(11,13)(12,16)(14,15)(17,21)(18,20)(19,22)(23,24)(25,26,31,33)(27,36,38,32)(28,30,39,34)(29,35,40,37)(1,2)(3,4)(5,6)(7,8)(12,19)(16,22)(18,23)(20,24)(25,27,31,38)(26,32,33,36)(28,29,39,40)(30,37,34,35)(2,6)(3,7)(10,15)(11,17)(16,22)(18,23)(26,33)(28,39)(29,40)(32,36) involution — undirected(3,7)(4,8)(9,11,14,17)(10,13,15,21)(12,18,19,23)(16,20,22,24)(25,28,31,39)(26,34,33,30)(27,29,38,40)(32,35,36,37)(1,3)(2,4)(5,7)(6,8)(9,12,14,19)(10,16,15,22)(11,18,17,23)(13,20,21,24)(25,29)(26,35)(27,28)(30,36)(31,40)(32,34)(33,37)(38,39)(1,4)(2,3)(5,8)(6,7)(9,13)(10,17)(11,15)(12,20)(14,21)(16,23)(18,22)(19,24)(25,30,31,34)(26,28,33,39)(27,37,38,35)(29,36,40,32)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.