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