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