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