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