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