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