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