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