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