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