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