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