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