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