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