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