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