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