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