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