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