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