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