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