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