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