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