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