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