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