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