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