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