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