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