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