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