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