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