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