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