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