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