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