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