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