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