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