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