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