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