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)(11,18)(12,20)(13,15)(14,17)(16,22)(19,23)(21,24)(25,26,32,31)(27,28,34,30)(29,33,39,38)(35,36,40,37)(1,3,5,8)(2,6,4,7)(9,11,14,13)(10,15,17,18)(12,19,22,21)(16,23,20,24)(25,27)(26,30)(28,31)(29,35)(32,34)(33,37)(36,38)(39,40)(9,10)(11,18)(12,16)(13,15)(14,17)(19,24)(20,22)(21,23)(25,28,32,30)(26,27,31,34)(29,37,39,36)(33,40,38,35)(9,12)(10,16)(11,19)(13,21)(14,22)(15,23)(17,20)(18,24)(25,29,32,39)(26,33,31,38)(27,35,34,40)(28,36,30,37)(1,4,5,2)(3,7,8,6)(9,10)(11,15)(12,16)(13,18)(14,17)(19,23)(20,22)(21,24)(25,30,32,28)(26,34,31,27)(29,37,39,36)(33,40,38,35)(9,13,14,11)(10,15,17,18)(12,21,22,19)(16,23,20,24)(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.