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