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