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