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