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