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