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