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