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