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