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