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