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