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