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