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