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