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)(25,26,31,32)(27,29,33,37)(28,30,36,39)(34,35,38,40)(1,2)(3,8)(4,6)(5,7)(9,11)(10,13)(12,19)(14,17)(15,21)(16,18)(20,23)(22,24)(25,27,31,33)(26,29,32,37)(28,34,36,38)(30,35,39,40)(1,3,5,6)(2,4,7,8)(26,32)(27,33)(28,36)(35,40)(9,12,14,22)(10,15,18,20)(11,19,17,24)(13,21,16,23)(25,28)(26,30)(27,34)(29,35)(31,36)(32,39)(33,38)(37,40)(1,2)(3,4)(5,7)(6,8)(9,11)(10,16)(12,19)(13,18)(14,17)(15,23)(20,21)(22,24)(25,29,31,37)(26,33,32,27)(28,35,36,40)(30,38,39,34)(1,4)(2,6)(3,7)(5,8)(9,13,14,16)(10,17,18,11)(12,21,22,23)(15,24,20,19)(25,30)(26,28)(27,35)(29,34)(31,39)(32,36)(33,40)(37,38)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.