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