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