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