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