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