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