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