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