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