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