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