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