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