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