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