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