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