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