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