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