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