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