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