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