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