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