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