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