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