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