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