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