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