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