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