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