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