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