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