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