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