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