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)(25,26,30,35)(27,34,37,31)(28,33,29,32)(36,39,38,40)(1,2)(3,4)(5,6)(7,8)(9,10)(11,17)(12,20)(13,14)(15,19)(16,21)(18,22)(23,24)(25,27)(26,31)(28,36)(29,38)(30,37)(32,39)(33,40)(34,35) involution — undirected(2,6)(4,7)(10,14)(15,17)(16,20)(22,23)(25,28,30,29)(26,32,35,33)(27,36,37,38)(31,39,34,40)(9,11)(10,15)(12,18)(13,19)(14,17)(16,22)(20,23)(21,24)(25,26)(27,34)(28,32)(29,33)(30,35)(31,37)(36,40)(38,39) involution — undirected(1,3)(2,7)(4,6)(5,8)(9,12)(10,16)(11,18)(13,21)(14,20)(15,22)(17,23)(19,24)(25,29,30,28)(26,33,35,32)(27,36,37,38)(31,39,34,40)(1,4,5,7)(2,3,6,8)(9,10)(11,15)(12,16)(13,14)(17,19)(18,22)(20,21)(23,24)(25,27)(26,34)(28,38)(29,36)(30,37)(31,35)(32,39)(33,40)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.