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