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