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)(25,26,31,29)(27,34,33,30)(28,36,38,32)(35,37,39,40)(1,2,5,4)(3,7,8,6)(9,10)(11,16)(12,20)(13,18)(14,15)(17,21)(19,23)(22,24)(26,29)(27,33)(32,36)(35,39)(1,3,5,8)(2,6,4,7)(10,15)(11,19)(12,21)(13,24)(25,27)(26,30)(28,35)(29,34)(31,33)(32,37)(36,40)(38,39)(3,8)(6,7)(9,11,14,19)(10,16,15,23)(12,22,21,18)(13,20,24,17)(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)(10,17)(11,18)(13,23)(14,21)(15,20)(16,24)(19,22)(25,29,31,26)(27,34,33,30)(28,36,38,32)(35,40,39,37)(1,4,5,2)(3,6,8,7)(9,13,14,24)(10,18,15,22)(11,20,19,17)(12,23,21,16)(25,30,31,34)(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.