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