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