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)(11,14)(12,16)(13,17)(15,18)(19,22)(20,21)(23,24)(25,26,30,32)(27,28,33,31)(29,34,37,39)(35,36,40,38)(1,2)(3,6)(4,7)(5,8)(9,11)(10,14)(12,19)(13,18)(15,17)(16,22)(20,23)(21,24)(25,27,30,33)(26,31,32,28)(29,35,37,40)(34,38,39,36)(11,18)(14,15)(19,24)(22,23)(26,32)(27,33)(29,37)(36,38) involution — undirected(1,3,5,4)(2,6,8,7)(9,10)(11,14)(12,20)(13,17)(15,18)(16,21)(19,23)(22,24)(25,28,30,31)(26,33,32,27)(29,38,37,36)(34,35,39,40)(9,11)(10,15)(12,19)(13,18)(14,17)(16,23)(20,22)(21,24)(25,26)(27,31)(28,33)(29,34)(30,32)(35,38)(36,40)(37,39) involution — undirected(1,4,5,3)(2,7,8,6)(9,12)(10,16)(11,19)(13,21)(14,22)(15,23)(17,20)(18,24)(25,29)(26,34)(27,35)(28,36)(30,37)(31,38)(32,39)(33,40)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.