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)(25,26,30,32)(27,34,38,31)(28,29,35,33)(36,39,40,37)(1,2,5,6)(3,7,4,8)(9,11)(10,15)(12,19)(13,20)(14,18)(16,23)(17,22)(21,24)(25,27)(26,31)(28,36)(29,37)(30,38)(32,34)(33,39)(35,40)(1,3,5,4)(2,7,6,8)(11,18)(15,22)(19,23)(20,24)(26,32)(28,35)(31,34)(36,40)(1,3,5,4)(2,7,6,8)(9,11)(10,15)(12,19)(13,20)(14,18)(16,23)(17,22)(21,24)(25,28,30,35)(26,33,32,29)(27,36,38,40)(31,39,34,37)(1,4,5,3)(2,8,6,7)(9,12)(10,13)(11,19)(14,16)(15,20)(17,21)(18,23)(22,24)(25,27)(26,34)(28,36)(29,39)(30,38)(31,32)(33,37)(35,40)(9,13)(10,16)(11,20)(12,17)(14,21)(15,23)(18,24)(19,22)(25,29,30,33)(26,35,32,28)(27,37,38,39)(31,40,34,36)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.