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)(18,24)(19,23)(20,21)(25,26,31,34)(27,33,30,32)(28,37,38,29)(35,36,39,40)(3,7)(6,8)(9,11,15,13)(10,16,17,22)(12,21,18,19)(14,20,24,23)(25,27,31,30)(26,32,34,33)(28,35,38,39)(29,36,37,40)(1,2,5,4)(3,6,7,8)(10,17)(11,13)(12,18)(20,23)(28,38)(29,37)(35,39)(36,40)(1,3,5,7)(2,6,4,8)(9,12,15,18)(10,14,17,24)(11,19,13,21)(16,23,22,20)(25,28)(26,29)(27,35)(30,39)(31,38)(32,36)(33,40)(34,37)(1,4,5,2)(3,8,7,6)(9,13,15,11)(10,16,17,22)(12,21,18,19)(14,23,24,20)(25,29)(26,28)(27,36)(30,40)(31,37)(32,35)(33,39)(34,38)(9,14)(10,18)(11,20)(12,17)(13,23)(15,24)(16,19)(21,22)(25,30,31,27)(26,33,34,32)(28,39,38,35)(29,40,37,36)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.