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