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