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