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