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