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