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