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