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