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