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