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