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