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