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