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