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