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)(11,12)(13,17)(14,18)(15,16)(19,20)(21,23)(22,24)(25,26,30,33)(27,31,36,29)(28,32,38,40)(34,39,35,37)(9,10,14,18)(11,15,16,12)(13,17,22,24)(19,23,21,20)(25,27,30,36)(26,31,33,29)(28,35,38,34)(32,37,40,39)(1,2)(3,5)(4,6)(7,8)(25,28)(26,32)(27,34)(29,37)(30,38)(31,39)(33,40)(35,36) involution — undirected(3,7)(5,8)(9,11)(10,15)(12,18)(13,21)(14,16)(17,20)(19,22)(23,24)(25,28)(26,32)(27,35)(29,39)(30,38)(31,37)(33,40)(34,36) involution — undirected(1,3,4,7)(2,5,6,8)(9,12,14,15)(10,16,18,11)(13,20,22,23)(17,21,24,19)(25,27)(26,29)(28,34)(30,36)(31,33)(32,37)(35,38)(39,40)(1,2)(3,5)(4,6)(7,8)(9,13,14,22)(10,17,18,24)(11,19,16,21)(12,20,15,23)(25,29)(26,27)(28,37)(30,31)(32,34)(33,36)(35,40)(38,39)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.