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