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