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