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