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