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