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