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