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)(11,16)(12,20)(13,18)(14,15)(17,22)(19,21)(23,24)(25,26,30,33)(27,28,35,31)(29,37,38,32)(34,39,40,36)(3,7)(5,8)(10,15)(11,19)(17,20)(18,24)(25,27,30,35)(26,31,33,28)(29,34,38,40)(32,39,37,36)(1,2)(3,5)(4,6)(7,8)(10,15)(11,19)(17,20)(18,24)(25,28,30,31)(26,27,33,35)(29,36,38,39)(32,34,37,40)(1,3)(2,5)(4,7)(6,8)(9,11,14,19)(10,16,15,21)(12,18,22,24)(13,17,23,20)(25,27)(26,31)(28,33)(29,34)(30,35)(32,39)(36,37)(38,40)(1,2)(3,5)(4,6)(7,8)(9,12,14,22)(10,17,15,20)(11,18,19,24)(13,16,23,21)(25,29,30,38)(26,32,33,37)(27,34,35,40)(28,36,31,39)(9,13,14,23)(10,18,15,24)(11,20,19,17)(12,21,22,16)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.