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