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