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