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)(26,30)(28,36)(31,33)(34,40)(10,12)(14,15)(17,18,21,20)(19,24,23,22)(28,36)(32,37)(34,40)(38,39)(10,12)(11,16)(17,19,21,23)(18,22,20,24)(25,26)(27,33)(28,32)(29,30)(31,35)(34,39)(36,37)(38,40)(1,2)(3,5)(4,6)(7,8)(9,11)(10,14)(12,15)(13,16)(17,20,21,18)(19,22,23,24)(25,27,29,35)(26,31,30,33)(28,34,36,40)(32,38,37,39)(1,3,4,7)(2,5,6,8)(9,12,13,10)(11,14,16,15)(17,19)(18,22)(20,24)(21,23)(25,28)(26,32)(27,34)(29,36)(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.