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