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