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