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