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