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