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