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