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