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