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