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