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