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