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)(12,22,20,17)(14,18,24,23)(25,26,31,34)(27,32,30,40)(28,33,38,29)(35,36,37,39)(1,2,4,6)(3,5,8,7)(9,11,15,21)(10,16,13,19)(12,14,20,24)(17,18,22,23)(25,27,31,30)(26,32,34,40)(28,35,38,37)(29,39,33,36)(1,2)(3,5)(4,6)(7,8)(25,28,31,38)(26,29,34,33)(27,35,30,37)(32,39,40,36)(1,3)(2,5)(4,8)(6,7)(9,12,15,20)(10,17,13,22)(11,14,21,24)(16,18,19,23)(25,28)(26,33)(27,35)(29,34)(30,37)(31,38)(32,36)(39,40)(9,13,15,10)(11,16,21,19)(12,22,20,17)(14,18,24,23)(25,29,31,33)(26,28,34,38)(27,36,30,39)(32,37,40,35)(9,14)(10,18)(11,20)(12,21)(13,23)(15,24)(16,22)(17,19)(25,30,31,27)(26,32,34,40)(28,37,38,35)(29,39,33,36)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.