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