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