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