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