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