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