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