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