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