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