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