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