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