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