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