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