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