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