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