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