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