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