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