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