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