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