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