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