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